Association of the hypha-related protein Pra1 and zinc transporter Zrt1 with biofilm formation by the pathogenic yeast Candida albicans.

Bloodstream infection by the pathogenic fungus Candida albicans is a major health problem. Candidemia is often associated with medical devices, which can act as substrates for biofilm development. Biofilm-related infections are relatively difficult to treat because of their resistance to antimicrobial agents. It is therefore important to explore the mechanisms of biofilm formation. Dimorphism is a major contributor to biofilm formation in C. albicans. To determine whether the hypha-related proteins Pra1 (pH-regulated antigen) and Zrt1 (zinc transporter) are responsible for biofilm formation, the ability of pra1 and zrt1 deletion mutants to form biofilms was investigated. Biofilm formation by both deletion mutants was less than that of the wild-type strain. Because Pra1 and Zrt1 are also related to the zinc homeostasis system, the effects of adding zinc on biofilm formation were also examined. Biofilm formation was increased in the presence of zinc. These data suggest that Pra1 and Zrt1 regulate biofilm formation through zinc homeostasis.